Clutch device

Abstract

A clutch device includes a pressure plate movable toward or away from a clutch center and rotatable relative to the clutch center to press input-side rotating plates and output-side rotating plates. The clutch center includes center-side cam portions each including a center-side assist cam surface. At least one of the center-side cam portions includes at least one of a first center-side recess recessed in a first direction from a surface of center-side cam portion at a side of a second direction or a second center-side recess recessed in the second direction from a surface of the center-side cam portion at a side of the first direction.

What is claimed is: 
     
       1. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; and 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; 
 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction: 
 at least one of the center-side cam portions includes at least one of a first center-side recess or a second center-side recess, the first center-side recess being recessed in the first direction from a surface of the center-side cam portion at a side of the second direction, the second center-side recess being recessed in the second direction from a surface of the center-side cam portion at a side of the first direction; and 
 when seen in an axial direction of the output shaft, at least about one half of the first center-side recess overlaps with the center-side assist cam surface in a circumferential direction. 
 
     
     
       2. The clutch device according to  claim 1 , wherein the first center-side recess includes a first center-side slope parallel or substantially parallel to the center-side assist cam surface. 
     
     
       3. The clutch device according to  claim 2 , wherein
 at least one of the center-side cam portions includes a center-side slipper cam surface to cause the pressure plate to move away from the clutch center in order to reduce the pressing force between the input-side rotating plates and the output-side rotating plates; 
 assuming a direction from one center-side cam portion to another center-side cam portion in the center-side cam portions is a first circumferential direction and a direction from the another center-side cam portion to the one center-side cam portion is a second circumferential direction with respect to circumferential directions, the clutch center is operable to rotate in the first circumferential direction that is a direction from the center-side assist cam surface to the center-side slipper cam surface of one of the center-side cam portions; and 
 the first center-side slope tilts to approach the second direction in the second circumferential direction. 
 
     
     
       4. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; and 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; 
 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction:
 at least one of the center-side cam portions includes at least one of a first center-side recess or a second center-side recess, the first center-side recess being recessed in the first direction from a surface of the center-side cam portion at a side of the second direction, the second center-side recess being recessed in the second direction from a surface of the center-side cam portion at a side of the first direction; 
 
 at least one of the center-side cam portions includes a center-side slipper cam surface to cause the pressure plate to move away from the clutch center in order to reduce the pressing force between the input-side rotating plates and the output-side rotating plates; and 
 when seen in an axial direction of the output shaft, at least a portion of the second center-side recess overlaps with the center-side slipper cam surface. 
 
     
     
       5. The clutch device according to  claim 4 , wherein the second center-side recess includes a second center-side slope parallel or substantially parallel to the center-side slipper cam surface. 
     
     
       6. The clutch device according to  claim 5 , wherein
 assuming a direction from one center-side cam portion to another center-side cam portion in the center-side cam portions is a first circumferential direction and a direction from the another center-side cam portion to the one center-side cam portion is a second circumferential direction with respect to circumferential directions, the clutch center is operable to rotate in the first circumferential direction that is a direction from the center-side assist cam surface to the center-side slipper cam surface of one of the center-side cam portions; and 
 the second center-side slope tilts to approach the first direction in the first circumferential direction. 
 
     
     
       7. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; and 
 
 an outer peripheral wall located radially outward of the center-side cam portions; 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction: 
 at least one of the center-side cam portions includes at least one of a first center-side recess or a second center-side recess, the first center-side recess being recessed in the first direction from a surface of the center-side cam portion at a side of the second direction, the second center-side recess being recessed in the second direction from a surface of the center-side cam portion at a side of the first direction; and 
 the clutch center includes an oil passage penetrating the peripheral wall and having one end open radially inward to communicate with the second center-side recess and another end open radially outward to communicate with outside of the peripheral wall. 
 
     
     
       8. The clutch device according to  claim 7 , wherein the clutch center includes:
 a plurality of center-side fitting teeth holding the output-side rotating plates, projecting radially outward from an outer peripheral surface of the outer peripheral wall, and arranged in circumferential directions; and 
 a plurality of spline grooves each located between adjacent ones of the center-side fitting teeth; and 
 the oil passage is located in the spline grooves to penetrate the peripheral wall. 
 
     
     
       9. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; and 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; and 
 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction: 
 at least one of the center-side cam portions includes a first center-side recess and a second center-side recess, the first center-side recess being recessed in the first direction from a surface of the center-side cam portion at a side of the second direction, the second center-side recess being recessed in the second direction from a surface of the center-side cam portion at a side of the first direction. 
 
     
     
       10. The clutch device according to  claim 9 , wherein an end of the first center-side recess in the first direction is located ahead, in the first direction, of an end of the second center-side recess in the second direction. 
     
     
       11. The clutch device according to  claim 9 , wherein when seen in an axial direction of the output shaft, the first center-side recess and the second center-side recess do not overlap with each other. 
     
     
       12. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; and 
 
 a center-side cam hole penetrating a portion between adjacent ones of the center-side cam portions; 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction: 
 at least one of the center-side cam portions includes a first center-side recess that is recessed in the first direction from a surface of the center-side cam portion at a side of the second direction; and 
 when seen in an axial direction of the output shaft, at least about one half of the first center-side recess overlaps with the center-side cam hole in a circumferential direction. 
 
     
     
       13. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; and 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; 
 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction: 
 at least one of the center-side cam portions includes a first center-side recess that is recessed in the first direction from a surface of the center-side cam portion at a side of the second direction; and 
 at least one of the center-side cam portions includes a center-side slipper cam surface to cause the pressure plate to move away from the clutch center in order to reduce the pressing force between the input-side rotating plates and the output-side rotating plates; and 
 assuming a direction from one center-side cam portion to another center-side cam portion in the center-side cam portions is a first circumferential direction and a direction from the another center-side cam portion to the one center-side cam portion is a second circumferential direction with respect to circumferential directions, the clutch center is operable to rotate in the first circumferential direction that is a direction from the center-side assist cam surface to the center-side slipper cam surface of one of the center-side cam portions; and 
 the first center-side recess includes a first center-side slope that tilts to gradually approach the second direction in the second circumferential direction. 
 
     
     
       14. The clutch device according to  claim 13 , wherein the first center-side slope is parallel or substantially parallel to the center-side assist cam surface. 
     
     
       15. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; and 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; 
 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction:
 at least one of the center-side cam portions includes a second center-side recess that is recessed in the second direction from a surface of the center-side cam portion at a side of the first direction; 
 
 at least one of the center-side cam portions includes a center-side slipper cam surface to cause the pressure plate to move away from the clutch center in order to reduce the pressing force between the input-side rotating plates and the output-side rotating plates; 
 assuming a direction from one center-side cam portion to another center-side cam portion in the center-side cam portions is a first circumferential direction and a direction from the another center-side cam portion to the one center-side cam portion is a second circumferential direction with respect to circumferential directions, the clutch center is operable to rotate in the first circumferential direction that is a direction from the center-side assist cam surface to the center-side slipper cam surface of one of the center-side cam portions; and 
 the second center-side recess includes a second center-side slope that tilts to approach the first direction in the first circumferential direction. 
 
     
     
       16. The clutch device according to  claim 15 , wherein the second center-side slope is parallel or substantially parallel to the center-side slipper cam surface. 
     
     
       17. A clutch device to allow or interrupt transfer of a rotation driving force of an input shaft to an output shaft, the clutch device comprising:
 a clutch center housed in a clutch housing holding a plurality of input-side rotating plates to be rotationally driven together with the output shaft, the input-side rotating plates being operable to be rotationally driven by rotational driving of the input shaft; and 
 a pressure plate movable toward or away from the clutch center and rotatable relative to the clutch center to press the input-side rotating plates and output-side rotating plates, the input-side rotating plates and the output-side rotating plates being alternately arranged; wherein 
 the clutch center includes:
 an output shaft holding portion to which the output shaft is coupled; and 
 a plurality of center-side cam portions located radially outward of the output shaft holding portion and each including a center-side assist cam surface operable to generate a force in a direction of causing the pressure plate to approach the clutch center in order to increase a pressing force between the input-side rotating plates and the output-side rotating plates upon rotation relative to the pressure plate; and 
 
 assuming a direction in which the pressure plate approaches the clutch center is a first direction, and a direction in which the pressure plate moves away from the clutch center is a second direction: 
 at least one of the center-side cam portions includes a center-side recess that is recessed in the second direction from a surface of the center-side cam portion at a side of the first direction. 
 
     
     
       18. The clutch device according to  claim 17 , wherein
 the center-side cam portions include a center-side slipper cam surface to cause the pressure plate to move away from the clutch center in order to reduce the pressing force between the input-side rotating plates and the output-side rotating plates; and 
 the center-side recess is sandwiched between the center-side assist cam surface and the center-side slipper cam surface in a circumferential direction.